Macro conch_runtime::impl_trivial_builtin_cmd

macro_rules! impl_trivial_builtin_cmd {
    (
        $(#[$cmd_attr:meta])*
        pub struct $Cmd:ident;

        $(#[$constructor_attr:meta])*
        pub fn $constructor:ident ();

        $(#[$future_attr:meta])*
        pub struct $Future:ident;

        $exit:expr
    ) => { ... };
}

Implements a builtin command which accepts no arguments, has no side effects, and simply exits with some status.